In-car entertainment can be provided by the vehicle head unit. The head unit typically comprises a radio, CD player, and other entertainment capabilities. The head unit will typically be connected to a vehicle antenna, for example for receiving radio waves from the exterior.
A vehicle head unit may communicate with mobile electronics belonging to a vehicle occupant, such as the driver or passenger. For example, there may be an AUX socket for connecting a personal music player such as an iPod to the head unit using a cable.
The desired functionalities of the head unit may change over time, for example as different forms of mobile electronics become more prevalent. However, replacing the head unit may be difficult, expensive, and may compromise the aesthetic appearance of the vehicle.